Other Psychoactive Drugs

Benztropine

Brand Name (Manufacturer)

Type of Drug

Used For

Benztropine is used for the treatment of the symptoms of Parkinson's disease. It is also used to prevent or treat the muscle spasms caused by certain drugs used to treat psychosis.

Parkinson's disease is an uncommon manifestation of toxoplasmosis encephalitis in people infected with HIV, and in these cases, the symptoms may be treated with benztropine.

General Information

Benztropine is classified as an anticholinergic drug because it blocks the activity of a nerve-impulse transmitter called acetylcholine. Muscle rigidity is one of the primary symptoms of Parkinson's disease. Benztropine blocks the nerve signals that cause the rigidity, allowing the muscles to relax. By a similar mechanism, benztropine can prevent or counteract the muscle spasms that occur as a side effect of some psychoactive drugs.

Benztropine is available as a solution for injection and as tablets for oral administration. The injectable drug is used where rapid action is necessary and in cases where the muscle rigidity makes taking the tablets difficult or impossible.

Treatment

As with all psychoactive drugs, the minimum effective dosage should be used. Therapy usually starts at a low dose and is increased gradually at five- or six-day intervals as necessary and tolerated. For Parkinson's disease, the effective dosage ranges from 0.5 to 6.0 mg per day, with most adults using 1 to 2 mg per day. For treatment of muscle spasms caused by psychoactive drugs, benztropine is used at a dosage of 1 to 4 mg, once or twice a day, adjusted for the individual.

Cautions and Warnings

Benztropine should not be used by anyone with a known allergy to it. It may impair the mental or physical abilities needed to operate dangerous machinery or drive an automobile.

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Because benztropine may prevent sweating and interfere with the body's internal heat control, it should be used with caution by people with chronic illness, a history of alcoholism, central nervous system disease, and people with inability to sweat. Benztropine should also be used with caution by people doing manual labor in a hot environment. In these cases the drug can cause heatstroke, which on occasion has been fatal.

Benztropine should be used with caution in people with heart disease, prostate disorders, difficulty urinating, or glaucoma. Although the drug does not appear to affect simple glaucoma, it may worsen angle-closure glaucoma and should not be used by people with this condition.

Side Effects

The most common side effects of benztropine include constipation, vomiting, nausea, dry mouth, and difficulty urinating. These can usually be eliminated or reduced in severity by lowering the dose of the drug.

Other side effects of benztropine include irregular heartbeat, confusion, disorientation, mental impairment, hallucinations, nervousness, depression, listlessness, numbness in the fingers, heatstroke, fever, and blurred vision. Occasionally, an allergic reaction such as a skin rash develops in people taking the drug.

Pregnancy/Breast-Feeding

Benztropine has not been formally studied in pregnant women or animals, but in clinical practice, there has been no evidence that the drug causes fetal harm. Pregnant women are encouraged to discuss the benefits and potential risks of benztropine with their physician before deciding to take the drug.

HIV may be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. Benztropine may reduce the amount of milk a woman can produce. In addition, infants are highly susceptible to the side effects of the drug. Women who must take the drug should discontinue breast-feeding.

Use In Children

Because children are more sensitive to the side effects of benztropine than adults, the drug is not recommended for anyone under the age of three years. Older children who use the drug should be carefully monitored for side effects.

Use in the Elderly

Older adults may be more susceptible to the side effects of the drug and may require reduced doses.

Drug Interactions

When benztropine is used with other psychoactive drugs, including phenothiazines (e.g., chlorpromazine), haloperidol, tricyclic antidepressants (e.g., amoxapine, amitriptyline, nortriptyline), or other anticholinergics (e.g., atropine), the risk of side effects is increased. In some cases, these combinations have been fatal.

Food Interactions

Oral benztropine is absorbed into the body most effectively when taken on an empty stomach, but it may be taken with food if it causes stomach upset.

Other Drugs Used for Similar Conditions

Other drugs used to treat the symptoms of Parkinson's disease include diphenhydramine, levodopa, bromocriptine, and carbidopa. The choice of drug generally depends on the severity of the condition, the health of the individual, and other drugs being concurrently used. In many cases, combinations of these drugs are more effective than using individual drugs alone.

Bupropion

Brand Name (Manufacturer)

Wellbutrin (Burroughs Wellcome)

Type of Drug

Psychoactive-antidepressant

Used For

Bupropion is used to treat depression in people who cannot take other medications.

General Information

Bupropion belongs to a class of drugs known as aminoketone antidepressants. It is chemically unrelated to tricyclic, tetracyclic, or other known classes of antidepressants. It is not known how bupropion works. It does not affect the cellular enzyme monoamine oxidase (MAO), which is the target of a class of antidepressants called MAO inhibitors. It raises brain levels of the neuro- transmitters serotonin and norepinephrine only weakly, which is the mechanism of action of another class of antidepressants that includes fluoxetine (Prozac).

Bupropion is generally used only after other drugs have failed, because people taking it have a higher risk of seizures than those taking other antidepressants.

Antidepressant medications are usually taken over long periods. It may take three to four weeks for antidepressants, including bupropion, to have an effect on depression. Bupropion accumulates in the body's tissues with prolonged use, and after it is discontinued, the drug takes about two weeks to get completely out of the body.

Bupropion is available as tablets for oral administration.

Treatment

Bupropion is usually taken at a dosage of 300 to 400 mg per day, divided into three or four doses. The total dose is divided into these small amounts to reduce the risk of seizures.

Cautions and Warnings

Bupropion should not be used by anyone with a known allergy to it or people who have a history of seizures or eating disorders. The drug should also not be taken when taking MAO inhibitors. At least fourteen days should elapse between discontinuing a MAO inhibitor and using bupropion.

In contrast to most other antidepressants, bupropion may cause weight loss. HIV-positive people who are already experiencing weight loss should consider using a different antidepressant.

Suddenly stopping bupropion may cause withdrawal symptoms or side effects.

Side Effects

The most serious side effect of bupropion is seizures. Approximately four out of every thousand people taking the drug experience seizures. The risk may be reduced if the total daily dose does not exceed 450 mg and if the drug is taken, as directed, in divided doses to reduce the maximum blood levels.

Other side effects of the drug include restlessness, agitation, anxiety, insomnia, confusion, hyperactivity, feelings of elation, delusions, hallucinations, or impaired mental function.

More than 28% of people treated with bupropion in clinical trials had loss of appetite and/or weight loss of more than five pounds.

Pregnancy/Breast-Feeding

Bupropion has not been formally studied in pregnant women. In animal studies it did not cause fetal harm, but it is not known whether the same would be true for humans. Pregnant women are encouraged to discuss the benefits and potential risks of bupropion with their physician before deciding whether or not to use the drug.

HIV may be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. Bupropion may pass through human milk and cause serious side effects in nursing children. Because of the potential toxicity of the drug, women should consider alternatives to breast-feeding while taking it.

Use In Children

The safety and effectiveness of bupropion in people under eighteen have not been formally studied.

Use in the Elderly

Older adults may be more susceptible to the side effects of the drug and may require reduced doses.

Drug Interactions

Bupropion is metabolized by the liver. Caution should be used when taking other drugs that affect the liver, including carbamazepine, cimetidine, phenobarbital, and phenytoin. There is some evidence of increased side effects when bupropion and L-dopa are used together.

Alcohol, tranquilizers, or other central nervous system depressants may intensify the effect of bupropion. Alcohol use also increases the risk of seizures caused by bupropion.

Food Interactions

Bupropion may be taken with or without food.

Other Drugs Used for Similar Conditions

For treatment of depression, there are many options, including tricyclic antidepressants (desipramine, nortriptyline, protriptyline, amoxapine, maprotiline, imipramine, trimipramine, doxepin), MAO inhibitors (tranylcypromine, phenelzine, isocarboxazid), serotonin reuptake inhibitors (fluoxetine, paroxetine, and sertraline), and stimulants such as methylphenidate. The appropriate choice varies from person to person and depends on age, physical health and condition, and other drugs being concurrently used.

Buspirone

Brand Name (Manufacturer)

BuSpar (Bristol-Myers Squibb)

Type of Drug

Psychoactive-antianxiety drug

Used For

Buspirone is used primarily for the short-term relief of anxiety. It is also occasionally used to treat the pain, fatigue, and cramps of premenstrual syndrome (PMS).

General Information

Buspirone is an antianxiety drug that is chemically different from and works by a completely different mechanism than most other antianxiety drugs. Buspirone is less sedating than a majority of antianxiety drugs and has no potential for addiction. It is also less likely to slow down the mental and physical reactions in the people who take it. It may be an appropriate choice for people who need to remain alert and for those with a potential for substance abuse.

Buspirone is available in tablets for oral administration.

Treatment

As with all psychoactive drugs, the lowest effective dosage of buspirone should be used. The recommended initial dose is 5 mg taken three times a day. The dose is usually increased gradually as necessary and as long as it is tolerated. Total daily doses of 20 to 30 mg are common after the condition has stabilized.

Cautions and Warnings

Buspirone should not be used by anyone with a known allergy to it. It is not recommended for people who are taking antidepressants of the monoamine oxidase (MAO) inhibitor class, because of the potential for serious side effects.

People who are taking benzodiazepine antianxiety drugs (alprazolam, diazepam, chlordiazepoxide, for example) and want to switch to buspirone should gradually reduce their dose under a doctor's supervision and stop taking the benzodiazepine before starting buspirone. This strategy reduces the risk of withdrawal symptoms from the benzodiazepines.

Although buspirone is less sedating than other antianxiety medications, drowsiness is still one of its side effects, and it is not possible to predict how an individual will react to the drug. People taking buspirone should be cautious about operating dangerous machinery or driving an automobile while on the drug.

Side Effects

Dizziness, nausea, headache, and nervousness were reported by 5% to 10% of people taking the drug in clinical trials. Light-headedness and excitability were reported by approximately 2% of people in clinical trials.

Other side effects that occur in more than 1% of people who use buspirone include chest pain, dream disturbances, ringing in the ears, sore throat, and nasal congestion. In fewer than 1% of people taking the drug, changes in blood pressure, redness and itching of the eyes, altered taste, altered smell, gas, changes in appetite, rectal bleeding, changes in urination patterns, menstrual irregularity, muscle cramps, muscle spasms, shortness of breath, changes in sex drive, allergic reactions, dry skin, weight changes (both gains and losses), and malaise were reported.

Pregnancy/Breast-Feeding

Buspirone has not been formally studied in pregnant women. In animal studies, the drug did not cause fetal harm, but it is not known whether this would be true for humans. Pregnant women are encouraged to discuss the benefits and potential risks of buspirone with their physician before deciding to take the drug.

HIV may be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. It is not known whether buspirone is excreted in human milk. It was, however, excreted in the milk of laboratory animals during testing. Because of the potential toxicity of the drug to their infants, women should consider alternatives to breast-feeding while taking it.

Use In Children

The safety and effectiveness of buspirone for children under the age of eighteen have not been formally studied in clinical trials.

Use in the Elderly

Although buspirone has not been formally studied in the elderly, several hundred people over the age of sixty-five participated in studies of buspirone for the general population, and no unusual, age-related increase in side effects was identified.

Drug Interactions

When used with MAO inhibitors (e.g., phenelzine or tranylcypromine), buspirone may increase the risk of serious elevations in blood pressure. Buspirone may increase haloperidol levels in the blood, potentially increasing the risk of side effects. The combination of buspirone and trazodone may cause liver toxicity.

Food Interactions

Food slows down the rate at which buspirone is absorbed into the body, but increases the total amount absorbed. Buspirone may be taken with or without food.

Other Drugs Used for Similar Conditions

The benzodiazepines (e.g., alprazolam, diazepam, chlordiazepoxide) are the most frequently used antianxiety medications. They are fairly safe, they work rapidly, and they don't have to be taken on an ongoing basis to be effective. The drugs in the class differ somewhat in the side effects they produce, their potencies, the time it takes for them to work, and the tendency for them to be addictive or cause withdrawal symptoms.

Buspirone is not addictive and is less likely to be sedating. On the other hand, it is not effective for many people, and in others it must be taken several times a day in order to be effective.

Haloperidol

Brand Name (Manufacturer)

Haldol (McNeil)

Type of Drug

Psychoactive-tranquilizer

Used For

Haloperidol is used for the management of the symptoms of psychotic disorders in children and adults. In children this may include treatment of hyperactivity, severe behavioral problems, inability to sustain attention, and an abnormally low tolerance for frustration. In adults, the treated disorders may include Tourette's syndrome, chronic schizophrenia, and phencyclidine psychosis.

General Information

Haloperidol affects a part of the brain called the hypothalamus. This part of the brain affects some of the automatic functions of the body, including temperature, metabolism levels, alertness, muscle tone, and hormone balance. It is not known exactly how the drug works to alleviate the symptoms of psychosis.

Haloperidol is available as tablets, liquid concentrate, and solution for injection.

Treatment

Most adults and children use the tablet form unless they have difficulty swallowing it. The solution for injection is used for severely agitated people to achieve a rapid response. This formulation has not been tested in children.

The dose of haloperidol must be adjusted for a person's age, condition, severity of illness, previous response to other psychoactive drugs, and other medications taken at the same time. Children and elderly adults with impaired kidney function may require lower doses. The optimal response is usually obtained by starting with a low dose and gradually increasing it.

Haloperidol decanoate is a long-acting form of the drug and is administered by deep injection into a large muscle once a month. It is generally used only after an individual has stabilized while taking the shorter-acting oral drug.

Cautions and Warnings

Haloperidol should not be used by people in severe central nervous system depression comatose states. It should also not be used by those with Parkinson's disease or who have a known allergy to the drug.

Tardive dyskinesia, a syndrome consisting of potentially irreversible, involuntary movements, may develop in people treated with haloperidol. The risk is correlated with length of therapy and total dose, but it is not possible to predict whether any individual will experience the side effect.

As with other central nervous system depressants, haloperidol may affect the mental and physical capacity to operate heavy machinery or drive an automobile.

Haloperidol should be used with caution in people with heart conditions because of the risk of low blood pressure and in those with a history of seizures or receiving anticonvulsant medication because haloperidol may increase the risk of seizures.

Side Effects

The most common side effect to haloperidol is drowsiness. Less commonly, haloperidol can cause jaundice, fever, bone-marrow toxicity, alteration in blood pressure, abnormal heartbeat, heart attack, faintness, and dizziness.

Haloperidol can cause serious neurological side effects that include spasms of the neck muscles, severe stiffness of the back, rolling of the eyes, convulsions, difficulty swallowing, and symptoms associated with Parkinson's disease.

Pregnancy/Breast-Feeding

Haloperidol has not been formally studied in pregnant women. In animal studies, it did cause some evidence of fetal harm, but it is not known whether this would be true in humans. There have been reports of birth defects in women taking haloperidol with other drugs that have the potential to cause fetal harm, but it is not known whether haloperidol itself caused the birth defects. Pregnant women are encouraged to discuss the benefits and potential risks of haloperidol with their physician before deciding to use the drug.

HIV can be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. Haloperidol is excreted at high concentrations in human milk. It is not recommended for nursing women.

Use In Children

Haloperidol has been used effectively in children without unexpected side effects.

Use in the Elderly

Tardive dyskinesia is a haloperidol-related side effect that most commonly occurs in elderly people who take the drug, particularly elderly women.

Older adults may be more susceptible to the side effects of the drug and may require reduced doses.

Drug Interactions

Irreversible brain damage has occurred in a small number of people treated with lithium and haloperidol. It is not known, however, whether the drugs actually caused the side effect.

The use of haloperidol with alcohol, sleeping pills, barbiturates, anesthetics, or narcotics may cause severe central nervous system depression and low blood pressure.

Haloperidol may reduce the blood-pressure-lowering effect of guanethidine. Mixing haloperidol with propranolol may result in unusually low blood pressure. Blood concentrations of tricyclic antidepressants may be increased when they are used with haloperidol, increasing the risk of side effects.

Food Interactions

Haloperidol is absorbed most effectively when taken without food, but food may be used if the drug causes stomach upset.

Other Drugs Used for Similar Conditions

Other drugs with antipsychotic and tranquilizing activity include thorazine, fluphenazine, mesoridazine, thioridazine, and trifluoperazine. In general, they are equally effective when given in therapeutically equivalent doses. The major differences are in the type and severity of side effects, which may be different from person to person.

Lithium

Brand Names (Manufacturers)

Type of Drug

Used For

Lithium is used to treat or prevent the manic phases of manic depression, a mental disorder in which a person's mood swings wildly from elation to depression.

Lithium has also been used but not approved to reduce or counteract the bone-marrow toxicity of AZT in people with HIV, although there is little clinical evidence to support this use.

General Information

Lithium is the only available effective drug treatment for mania. When ingested and absorbed into the body, lithium alters the way nerve cells transmit their signals. This action effectively controls the symptoms of mania within one to three weeks after starting the drug.

Certain drugs commonly used by people infected with HIV, including AZT, can be toxic to bone marrow, often resulting in deficiencies in white blood cells. Because one side effect of lithium is an increase in white blood cells, the drug has been tested as a potential therapy to reverse the bone-marrow toxicity of AZT. Encouraging results in studies in animals prompted the start of clinical trials in humans. In one study, twenty volunteers were randomly chosen to receive AZT and either lithium at a dose of 300 mg twice a day or a placebo, for an average of twenty-four weeks. While the group receiving lithium had a transient increase in neutrophil counts six weeks after starting therapy, by the end of twenty-four weeks of treatment there was no difference in the counts of neutrophils or CD4+ cells between groups. This lack of long-term effect dampened the interest in lithium as a treatment for AZT toxicity.

In the meantime, other drugs that stimulate white blood cell production have become available. One, called G-CSF, is now widely used for the condition.

Lithium is available in capsules, controlled-release tablets, and syrup.

Treatment

Lithium is usually started with the immediate-release capsules and switched to the controlled-release tablets after the condition has stabilized. The immediate-release capsules are usually taken three or four times a day. The controlled-release tablets need to be taken only twice a day.

The optimal dose must be determined for each person, but most people take around 1,800 mg per day for acute episodes of mania. For long-term control after the condition has stabilized, the adult dose ranges from 600 to 1,200 mg per day.

When switching from the capsules to the tablets, it is important that the same total daily dose be given.

Cautions and Warnings

Lithium should not be used by anyone with a known allergy to it. In addition, it should generally not be used by people with significant kidney or heart disease, severe debilitation, or sodium deficiency because the risk of side effects is high in these people.

In most people, the effective dose of lithium is close to the dose that causes severe toxicities. In general, people taking the drug will be closely monitored by their physician to maintain appropriate levels of the drug in their blood.

People who experience diarrhea, nausea, vomiting, tremors, loss of coordination, drowsiness, or muscle weakness while taking lithium should contact their physicians as soon as possible. People with HIV may experience these symptoms as a result of their disease or other drugs being taken, but they may also be the early warning signs of lithium toxicity.

Side Effects

The side effects of lithium are generally dose-related, occurring more frequently and with greater severity when higher concentrations of lithium are in the blood. Hand tremors, frequent urination, mild nausea, general discomfort, and mild thirst may occur during initial therapy. These side effects usually subside with continued treatment or dose reductions. If they persist, the drug should be stopped.

Diarrhea, vomiting, drowsiness, muscle weakness, lack of coordination, giddiness, ringing in the ears, and blurred vision may occur at therapeutic levels of the drug. At dosages higher than recommended, severe side effects may occur.

Pregnancy/Breast-Feeding

Lithium can cause severe fetal harm and should not be taken during pregnancy, particularly during the first trimester. As many as 8% to 9% of babies exposed to lithium in the womb may develop heart defects. Other birth defects observed include brain and spine malformations. Women of childbearing age are encouraged to use effective contraception while taking the drug.

HIV may be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. Lithium passes into breast milk. Because of the potential toxicity of the drug, women should consider alternatives to breast-feeding while using it.

Use In Children

Lithium has not been formally studied in children under the age of fifteen, so no recommendations regarding its use in them can be made.

Use in the Elderly

Older adults may be more susceptible to the side effects of the drug and may require reduced doses. Even when lithium blood levels are within the recommended range, elderly people are at higher risk of the drug's side effects than the general population.

Drug Interactions

Haloperidol may increase the blood levels of lithium. This combination has caused weakness, fatigue, and confusion in some people, rarely resulting in permanent damage.

Lithium may reduce chlorpromazine levels in the blood, potentially reducing its effectiveness. Chlorpromazine may increase lithium levels in the blood, potentially resulting in increased side effects.

Sodium bicarbonate, acetazolamide, urea, mannitol, and theophylline neutralize the effect of lithium. Verapamil may reduce both the blood levels and toxicity of lithium.

Methyldopa, fluoxetine, carbamazepine, thiazide and loop diuretics, metronidazole, enalapril, captopril, and some arthritis medications like indomethacin or piroxicam may increase the effects of lithium.

Lithium may increase the blood levels of tricyclic antidepressants such as amoxapine, amitriptyline, desipramine, or maprotiline.

Food Interactions

For best absorption, lithium should be taken immediately after food or milk. Because lithium can cause a reduction in body salt levels, it is important to maintain a well-balanced diet.

Other Drugs Used for Similar Conditions

Lithium is the only available drug treatment for mania. For AZT-induced white blood cell deficiencies, the colony-stimulating factor G-CSF is the drug of choice.

Methylphenidate

Brand Name (Manufacturer)

Ritalin (Ciba)

Type of Drug

Psychoactive-stimulant

Used For

Methylphenidate is a central nervous system stimulant used to treat attention-deficit disorders, primarily in children. It is also used in narcolepsy, a disorder involving uncontrollable sleep attacks or desire to sleep. It is also occasionally used to treat depression in people who do not respond to other medication.

Methylphenidate is also occasionally used without approval by people with HIV for the treatment of AIDS dementia complex.

Methylphenidate is available as tablets for oral administration.

General Information

Attention-deficit disorder, which occurs primarily in young boys, involves moderate-to-severe distractibility, short attention span, hyperactivity, wide emotional swings, and impulsivity. A total treatment program for the disorder typically includes psychological, educational, and social measures as well as drug therapy.

Methylphenidate is a psychostimulant. It has proven useful in people who are withdrawn or apathetic. It works more rapidly than drugs in other classes of antidepressants.

Treatment

The dosage must be adjusted for each person. The standard dose for adults and adolescents is 20 to 30 mg per day. Some people may require up to 60 mg per day. The drug is also available in a slow-release (SR) form. The SR tablets must be swallowed whole, never crushed or chewed. The SR tablets can replace standard tablets when eight-hour dosing is necessary.
Children are generally given small initial doses with gradual weekly increments as necessary, if they don't experience serious side effects. The recommended dose for children is 5 mg twice daily before breakfast and lunch, with gradual dose increments of 5 to 10 mg each week. A daily dose over 60 mg is not recommended for children.

In treatment of symptoms of AIDS dementia complex, doses of 5 to 10 mg per day are often sufficient to alleviate apathy and to increase energy, concentration, and appetite.

Cautions and Warnings

People with marked anxiety, tension, or agitation should not take the drug, since it may aggravate these symptoms. People who know they are allergic to it, have glaucoma, motor tics, or a family history of Tourette's syndrome should not take the drug.

There is some clinical evidence that suggests methylphenidate increases the likelihood of seizures in people with a prior history of seizures.

The drug should be used with caution in people with high blood pressure.

Chronic use of methylphenidate can cause dependency. Abuse can cause psychotic episodes.

Side Effects

Nervousness and insomnia are the most frequent side effects. Hypersensitivity, anorexia, nausea, dizziness, heart palpitations, headache, drowsiness, high blood pressure and pulse changes, rapid heartbeat, angina, irregular heart rhythm, abdominal pain, and weight loss during prolonged therapy have been observed. There have been rare reports of Tourette's syndrome and toxic psychosis.

Pregnancy/Breast-Feeding

Methylphenidate has not been formally studied in pregnant women. It passes through the placenta into the fetal blood circulation, but it has not been found to cause birth defects. Pregnant women are encouraged to discuss the benefits and potential risks of methylphenidate with their physician before deciding to use the drug.

HIV can be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. It is not know if methylphenidate passes into human milk, but the drug has caused no significant problems among breast-fed infants.

Use In Children

Methylphenidate has not been studied in children under six. Children six and older are generally treated at the dosages listed above. The long-term effects in children have not been well established. Side effects in children may occur more frequently than in adults.

Use in the Elderly

No changes in dosage or administration are recommended for elderly people.

Drug Interactions

Methylphenidate may decrease the effectiveness of the blood-pressure medicine guanethidine. It may inhibit the metabolism of the blood-thinner warfarin, anticonvulsants (phenobarbital, diphenylhydantoin, primidone), phenylbutazone, and tricyclic antidepressants (imipramine, clomipramine, desipramine).

Food Interactions

Methylphenidate should be taken thirty to forty-five minutes before meals to maximize absorption of the drug into the body.

Other Drugs Used for Similar Conditions

To alleviate symptoms of depression, a number of antidepressants, such as fluoxetine, are available. For treatment of AIDS dementia complex, haloperidol may be used. Amphetamines are sometimes prescribed to increase energy and improve concentration.

Venlafaxine

Brand Name (Manufacturer)

Effexor (Wyeth-Ayerst)

Type of Drug

Psychoactive-antidepressant

Used For

Venlafaxine is used to treat depression.

General Information

Venlafaxine is an antidepressant chemically unrelated to other antidepressants such as the tricyclics or monoamine oxidase (MAO) inhibitors. Venlafaxine is thought to work by increasing the concentration of a number of different neurotransmitters in the brain.

Venlafaxine is available as tablets for oral administration.

Treatment

The recommended starting dose of venlafaxine is 75 mg per day, taken in two or three divided doses. As needed and tolerated, the dose may be increased up to 150 mg or 225 mg per day. When increasing the dose, increments of up to 75 mg per day should be made at intervals of at least four days. People with kidney or liver disease may need to take reduced dosages.

When discontinuing venlafaxine, the risk of withdrawal symptoms is lowest if the drug is tapered off slowly. The drug should be discontinued under the guidance of a physician.

When switching from a MAO inhibitor antidepressant, at least fourteen days should elapse between stopping the MAO inhibitor and starting venlafaxine. Similarly, venlafaxine should be stopped for seven days before starting an MAO inhibitor antidepressant.

Cautions and Warnings

Venlafaxine should not be used by anyone with a known allergy to it. Taking venlafaxine concomitantly with MAO inhibitors may cause severe, potentially fatal side effects.

Because venlafaxine causes increased blood pressure, people taking the drug should have their blood pressure monitored routinely.

In people with a history of mania, venlafaxine may induce manic episodes.
Although venlafaxine did not impair thinking or motor skills in clinical trials, people taking the drug should refrain from driving or operating dangerous machinery until they are reasonably certain the drug does not cause drowsiness or sedation in them.

Side Effects

The most common side effects of venlafaxine include nausea, constipation, loss of appetite, drowsiness, dry mouth, dizziness, insomnia, nervousness, headache, weakness, sweating, abnormal ejaculation, and diarrhea. Less common side effects include vomiting, anxiety, tremors, confusion, blurred vision, and impotence.

Pregnancy/Breast-Feeding

Venlafaxine has not been formally studied in pregnant women. In animal studies, it did not cause fetal harm, but it is not known whether the same would be true in humans. Pregnant women are encouraged to discuss the benefits and potential risks of the drug with their physician before deciding to use it.

HIV can be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. It is not known whether venlafaxine is excreted in human milk. Because of the potential toxicity of the drug, women are encouraged to consider alternatives to breast-feeding while using it.

Use In Children

Venlafaxine is not recommended for use in those under eighteen years of age, because the safety and effectiveness of the drug for them have not yet been established.

Use in the Elderly

In clinical trials, no overall differences in safety or effectiveness were observed between older and younger adults. However, older adults may be more susceptible to the side effects of the drug and may require reduced doses.

Drug Interactions

The use of venlafaxine and MAO inhibitors greatly increases the risk of serious, potentially fatal side effects.

Food Interactions

The manufacturer recommends taking venlafaxine with food.

Other Drugs Used for Similar Conditions

For treatment of depression, there are many options, including tricyclic antidepressants (desipramine, amitriptyline, protriptyline, amoxapine, maprotiline, imipramine, trimipramine, doxepin), MAO inhibitors (tranylcypromine, phenelzine, isocarboxazid), serotonin reuptake inhibitors (fluoxetine, paroxetine, and sertraline), and stimulants such as methylphenidate. The appropriate choice varies from person to person and depends on age, physical health and condition, and other drugs being concurrently used.

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